Internal combustion engines are not self-starting and thus assistance is provided so that the engine can start and thereafter continue to operate. As a number of internal combustion engines require energy to be provided to continue to operate (e.g., generation of an ignition spark) as well as to run other auxiliary devices (e.g., lights, computer, radios, clock, navigation system, etc.), devices (e.g., generators, alternators) are provided with the engine to generate such energy. As shown in FIG. 1A, the starter/generator system for a number of years was a separate starter motor to start the engine and an alternator/generator that generated electrical energy to run electrically powered devices and charge the battery.
The starter motor was mechanically coupled to the flywheel by gearing. Thus, when the engine was to be started (e.g., by turning the ignition key to “start”) the battery was coupled to the starter motor. The rotation of the starter motor caused the flywheel which in turn caused the crankshaft to rotate thereby creating conditions within the engine to start the combustion process. In the starting process, the clutch also was operated so as to decouple the flywheel from the gear box so that the rotational energy being provided by the starter motor was not delivered to portions of the powertrain downstream of the gear box.
The alternator was operably coupled to the crankshaft by a circuitous belt. When the engine was running the rotational motion of the crankshaft caused the belt to run in a circuitous path. This continuous circuitous movement of the belt in turn caused the alternator to operate and to generate electrical energy. Typically, rectification circuitry and regulation circuitry was provided, so that the alternator output was a DC voltage and so the voltage output was in a desired DC voltage range.
In recent years efforts have been undertaken to integrate the starter-generator (ISG), such as shown for example in FIG. 1B. In this system, a single device is provided for both the starter motor and generator—a starter/alternator. This starter/alternator is mechanically coupled to the crankshaft using a circuitous belt much like that described above in connection with FIG. 1A.
When the engine is to be started, the starter/alternator is configured and operated so as to function as a motor. In other words, the battery is electrically coupled to the starter/alternator so it rotates as a motor. Such rotation in turn is imparted to the crankshaft via the movement of the belt, thus creating conditions contusive to engine starting. The clutch also is operated so as to decouple the flywheel from the gear box as is described above. After the engine is started, the starter/alternator is re-configured so that it is thereafter operated as the alternator. Because of concerns of belt stretching and slippage over time, such a system can be less effective or reliable for starting as compared to systems in which the starter motor is mechanically coupled to the flywheel.
Referring now to FIG. 1C there is shown another ISG, where the starter/alternator is mechanically coupled to the flywheel and thus the engine's crankshaft via a clutch. As described above, another clutch is provided between the starter/alternator and the gearbox in order to isolate other portions of the power train (e.g., gearbox, wheels, etc.) from the starter/alternator.
When the engine is to be started, the starter/alternator is configured and operated so as to function as a motor. In other words, the battery is electrically coupled to the starter/alternator so as to cause it and the flywheel to rotate. Such rotation of the flywheel causes the crankshaft to rotate, thereby creating conditions conducive to engine starting. After the engine is started, the starter/alternator is again configured so that it is thereafter operated as the alternator. Such an ISG also can be configured so as to create a hybrid engine so that the starter/generator can be used to provide additional power to the power train.
As the starter/alternator and additional clutch are provided between the flywheel and gearbox, this in effect increases the length of the engine. Such an increase in length affects layout and design of the automobile so that the increased length can be accommodated. Such concerns are of particular importance for cars which are front wheel driven because the engines are usually transverse mounted.
There is found in US Pub. No. 2009/0091137 a generator equipped engine in which the generator is external to the engine and coupled or mounted to the crankcase of the engine. The generator includes a flywheel that functions as the motor rotor and a stator that is in fixed relation to the crankcase. The generator flywheel is operably coupled to the crankshaft so that movement of the crankshaft causes the generator flywheel to rotate.
There is found in US Pub. No. 2004/0084978 a magento-generator and a method for manufacturing same. Such a magneto-generator includes a bowl-shaped flywheel, a plurality of magnets mounted on an inner peripheral surface of the flywheel, a resin filled around each of the individual magnets for fixedly securing the magnets to the flywheel as integral parts thereof, and a generator coil disposed within the bowl-shaped flywheel in opposition to the magnets for generating electric power under the action of electromagnetic induction brought about through cooperation with the magnets. In use, a hub or boss of the flywheel that is centrally located is operably coupled to a rotor or rotatable shaft (e.g., crank shaft of an internal combustion engine). In this way, rotation of the rotor/shaft causes the flywheel to rotate thereby generating electrical power. much as is done with a conventional motor generator set.
It thus would be desirable to provide a new starter/motor/generator for a reciprocating engine such as an internal combustion engine and methods related thereto. It would be particularly desirable to provide such a starter/motor/generator that is crank-web mounted and is linearly segmented. It also would be desirable to provide such a starter/motor/generator that is capable of providing torque fill while the reciprocating engine is concurrently running.